A lot of key monopolies today are monopolies of intellectual property created by US patent and copyright laws. Bernie Saunders has proposed legislation that would make all drugs generic-essentially a federally funded system of prizes for drug research and buying drug patents via eminent domain. That basic approach could be applied to companies like Intel, Microsoft, Oracle. Basically require that key technologies be sold to the public via eminent domain-which would make it much easier to have a variety of companies active in those niches. I think it also might in time be applied to some financial areas too.

Another big issue is containing concentrations of wealth. Many big companies are essentially the expressions of one or a few very wealthy people. Taxing assets above a generous deduction would contain some of that very simply. Bill Gates would find himself paying $500 Million/year in taxes-and couldn't escape that my parking assets in a pet foundation. Big oil and mining companies tend to be extremely asset intensive.